
6
INSTALLATION / HYBRID NULL:
Once you've mounted your AC-3 and wired the power and Telco connections it is ready for the next to last
step,thehybridnulladjustment. This is accomplishedbymonitoringtheAC-3's audio output connectionwith
a console input, an amplified speaker, an o'scope or even an analog AC voltmeter. Dial up the coupler then
trigger the built-in tone generator (press S1 for stock AC-3). Adjust the Null Pot (VR1, besdie the RJ-11
connector)potforavisibleoraudiblenull. Thenull adjustment may have to be repeated if youchangephone
lines attached to the AC-3 or if your phone lines are modified, changed , or repaired by your telephone
company. Once you've set the null, you can attach your outbound audio source (if desired) and your AC-3 is
ready to use.
OPERATION
YourinstalledAC-3willremaindormantuntil it either detects incoming rings or you press the manual pickup
switch S1, or its remote control equivalent.
Unless the BEEP Enable jumper (J3) is removed, the unit will beep down the telephone line at pickup.
The Green ONLINE LED stays lit for the duration of the call.
The caller can stay ONLINE as long as desired.
Whenthecaller hangsup -your AC-3 shouldhang upeither instantly orwithin abouttwelve secondsdepending
on the variety of Central Office switching gear your telephone company uses. If it just hangs on the line
interminably, you may be in one of the very few areas where the local telephone company does not employ
what is typically known as CPC, short for Calling Party Control. You can test for CPC by removing the
telephone line from the AC-3. If it hangs up reliably each time the line is disconnected, but won't hang up
when it's connected to the phone line, then you're probably not getting CPC from your telephone co. If this
occurs see Appendix A near the end of the manual for your options.
If you'd like to slave a relay on the OPTO O/C output or the callend output, remember that the emitters of Q3
(the opto's slaved transistor) and Q4 (callend) are tied to the AC-3's ground buss. Please use a snuffer diode
to protect the transistors from inductive kick.
TROUBLESHOOTING
Ifyou are having trouble with your AC-3 please try to characterize the trouble before calling for tech support.
Things to check:
Observations: Likely Cause
NO Power LED (the red LED that Power supply dead.
sticks through the flat front panel).
Unit doesn't pick up after prescribed number Optocoupler U1 dead.
of rings and ring LED doesn't light during rings.
Unit picks up then immediately hangs up. 1/2 of optocoupler U1 dead.
Unit refuses to hang up. You're on a PBX or telco line without
CPC. See above on this page for details.
Ring/Online (green) LED not on, but unit picks up MOV shorted.
phoneline anytime phone line is connected.